Application Of A Remote Sensing Technique In Estimating Evapotranspiration For Nyazvidzi Sub- Catchment., Zimbabwe

The integration of Remote Sensing and ground data into hydrological and cropwater requirement models enables water resources managers to adequately quantify the availability of water for irrigation in space and time. The SEBS algorithm was used to derive actual evapotranspiration estimates using MODIS images to assess cropwater requirements in the Ruti irrigation scheme after validation with ground based evapotranspiration measurements. Results show that actual evapotranspiration computed using SEBS (EToS) were comparable to those obtained using Penman Monteith method (R2=0.96). The Kendall’s tau test showed that there is significant statistical association (α = 0.05) between Pan Coefficient (Kp) values determined using EToS and EToPM and Kp values from the Snyder equation. In conclusion, the study highlights the potential use of GIS and remote sensed data for catchment management, planning and irrigation scheduling at irrigation scheme level. Welch’s t test showed that there is no evidence to reject Ho: Kp determined from EToPM – Kp from EToS = 0. The above is crucial in the evaluation and comparison of performance of different irrigation systems in the country for food security and improvement of livelihoods in the light of integrated water resources management

Assessment of occupational exposure to airborne particulates otherwise not classifiable at an iron and steel industry in Zimbabwe

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Upgrading wineries to biorefineries within a Circular Economy perspective: An Italian case study

In the challenge of transforming waste into useful products that can be re-used in a circular perspective, Italian wine industry can represent a suitable model for the application of the bioeconomy principles, including the valorisation of the agricultural and food waste. In the present study, a comprehensive environmental assessment of the traditional production of wine was performed and the potentiality of a biorefinery system, based on winery waste and aimed at recovering useful bio-based products, such as grapeseed oil and calcium tartrate, was examined through Life Cycle Assessment (LCA). The wine company "I Borboni", producing Asprinio wine in the Campania Region (Italy), was proposed as a case study. The hotspots of the linear production system were identified and the bottling phase, in particular the production of packaging glass, resulted to contribute to the generation of impacts at 63%, on average, versus 14.3% of the agricultural phase and 22.7% of the vinification phase. The LCA results indicated human carcinogenic toxicity, freshwater eutrophication and fossil resource scarcity impact categories as the most affected ones, with normalized impacts amounting to 9.22E-03, 3.89E-04 and 2.64E-04, respectively. Two side production chains (grapeseed oil and tartrate production) were included and circular patterns were designed and introduced in the traditional production chain with the aim of valorising the winery residues and improving the overall environmental performance. By implementing the circular approach, environmental impacts in the global warming, freshwater eutrophication and mineral resource scarcity impact categories, in particular, resulted three times lower than in the linear system. The results achieved demonstrated that closing the loops in the wine industry, through the reuse of bio-based residues alternatively to fossil-based inputs within the production process, and integrating the traditional production system with new side production chains led to an upgrade of the wineries to biorefineries, towards more sustainable production patterns. (c) 2021 Elsevier B.V. All rights reserved

Waste management through life cycle assessment of products

The rapid growth of a population in a country can contribute to high production of waste. Municipal waste and industrial waste can bring unhealthy and unpleasant environment or even diseases to human beings if the wastes are not managed properly. With increasing concerns over waste and the need for 'greener' products, it is necessary to carry out Life Cycle Assessments of products and this will help manufacturers take the first steps towards greener designs by assessing their product's carbon output. Life Cycle Assessment (LCA) is a process to evaluate the environmental burdens associated with a product, process or activity by identifying and quantifying energy and materials used and wastes released to the environment, and to assess the impact of those energy and material used and released to the environment. The aim of the study was to use a life cycle assessment approach to determine which waste disposal options that will substantially reduce the environmental burdens posed by the Polyethylene Terephthalate (PET) bottle. Several important observations can be made. 1)Recycling of the PET bottle waste can significantly reduce the energy requiredacross the life cycle because the high energy inputs needed to process the requisite virgin materials greatly exceeds the energy needs of the recycling process steps. 2)Greenhouse gases can be reduced by opting for recycling instead of landfilling andincineration. 3)Quantity of waste emissions released from different disposal options was identified. 4)Recycling is the environmentally preferable disposal method for the PET bottle. Industry can use the tools and data in this study to evaluate the health, environmental, and energy implications of the PET bottle. LCA intends to aid decision-makers in this respect, provided that the scientific underpinning is available. Strategic incentives for product development and life cycle management can then be developed

Biogas from source separated organic waste within a circular and life cycle perspective. A case study in Ontario, Canada

Abstract The appropriate transformation and valorisation of biogas offers environmental and economic opportunities in a future with restrictions upon fossil-based fuels and materials. The LCA method was used to quantify and compare the potential environmental impacts of an AD plant incorporating biogas co-generation and upgrading options, namely AD-CHP and AD-RNG. Using an average Anaerobic Digestion facility in Ontario, Canada, modelled after real facilities, as a case study, electricity and steel were identified as potential hotspot input materials carrying a disproportionate environmental burden for biogas production. With a system expansion approach, the biogas was subsequently utilized to produce (1) both heat and electricity using a Combined Heat and Power (CHP) system, or (2) upgraded to renewable natural gas (also called biomethane) through chemical amine scrubbing, respectively. In comparing the biogas co-generation and upgrading options, the AD-CHP alternative resulted in a lesser environmental load, two times lower when compared to the AD-RNG biomethane recovery option. Furthermore, the avoided burden of producing fossil-based electricity, natural gas, and chemical fertilizer was analyzed and compared against their renewable counterparts. Significant reductions in emissions and in the depletion of fossil fuels were achieved, thus confirming the positive efforts of diverting organic waste from landfills to reduce organic waste disposal impacts and improve the management of organic waste. The analysis has provided useful insights to bioenergy project developers, policy makers and the scientific community regarding the processing of source separated organic waste, biogas production, and its upgrading alternatives in a circular economy perspective

Potential energy savings from circular economy scenarios based on construction and agri-food waste in Italy

In this study, our aim was to explore the potential energy savings obtainable from the recycling of 1 tonne of Construction and Demolition Waste (C&DW) generated in the Metropolitan City of Naples. The main fraction composing the functional unit are mixed C&DW, soil and stones, concrete, iron, steel and aluminium. The results evidence that the recycling option for the C&DW is better than landfilling as well as that the production of recycled aggregates is environmentally sustainable since the induced energy and environmental impacts are lower than the avoided energy and environmental impacts in the life cycle of recycled aggregates. This LCA study shows that the transition to the Circular Economy offers many opportunities for improving the energy and environmental performances of the construction sector in the life cycle of construction materials by means of internal recycling strategies (recycling C&DW into recycled aggregates, recycled steel, iron and aluminum) as well as external recycling by using input of other sectors (agri-food by-products) for the manufacturing of construction materials. In this way, the C&D sector also contributes to realizing the energy and bioeconomy transition by disentangling itself from fossil fuel dependence

Spatial mapping of hepatitis C prevalence in recent injecting drug users in contact with services.

In developed countries the majority of hepatitis C virus (HCV) infections occur in injecting drug users (IDUs) with prevalence in IDUs often high, but with wide geographical differences within countries. Estimates of local prevalence are needed for planning services for IDUs, but it is not practical to conduct HCV seroprevalence surveys in all areas. In this study survey data from IDUs attending specialist services were collected in 52/149 sites in England between 2006 and 2008. Spatially correlated random-effects models were used to estimate HCV prevalence for all sites, using auxiliary data to aid prediction. Estimates ranged from 14% to 82%, with larger cities, London and the North West having the highest HCV prevalence. The methods used generated robust estimates for each area, with a well-identified spatial pattern that improved predictions. Such models may be of use in other areas of study where surveillance data are sparse

The southern African poultry value chain : corporate strategies, investments and agro-industrial policies

Abstract: Following various regional investments in the last decade, production and participation in the poultry value chain in southern Africa has increased. One of the factors that determines entry into, and success in, a global value chain is the governance structure. This paper adopts a modular approach to analyse the governance structures in the poultry value chains in Botswana, South Africa, Zambia and Zimbabwe. A key finding is that various stakeholders have an influence on the regional poultry value chain in southern Africa, with the sources of influence depending on the formality of structures within the value chain

Bridging the gap between energy consumption and the indoor environmental quality of a 1960s-educational building

The fundamental purpose of a building has evolved from merely providing protection from external environmental climate to more emphasis on integrating building services through building regulations to provide the synergy of comfort, efficiency and safety to the indoor environment. This research recognizes the rising demand and increasing quality of indoor environmental quality (IEQ) in the modern society compared to the acceptable level of previous traditional buildings. Generally due to its varied operations, educational buildings, in this case University libraries have its own set of challenges and barriers such as minimizing damages and decay of books and maintaining indoor conditions with an oversight of providing good IEQ to occupants. This paper presents a detailed evaluation of a 1960s-educational library with 24-hour access at the University of Reading. Through in-situ measurements, modelling and simulations of the building’s energy consumption, IEQ parameters and occupancy patterns, investigations have been performed. Varied scenarios using the Integrated Environmental Solution (IES) software were also investigated. The findings illustrate that due to mixed façade configuration (i.e. sandstone and bricks) there is the unflinching need to balance aesthetics of the facade and functionality of a building to reduce excessive energy use via heating, without compromising on occupant comfort and well-being Although it is envisaged that refurbishing the library building will provide energy savings of up to 40%, this is farfetched and can only be achieved at the detriment of occupant comfort levels as evident in the simulation results, where these savings could not be realised. This paper further discusses the methods, scenarios, and results of ensuring good IEQ, comfort and energy efficiency are not been seen as mutually exclusive. This study forms part of ongoing research into the impact of educational buildings

Field performance of spider plant (Cleome gynandra l) under different agronomic practices

Field experiments were carried out at Kaguvi Vocational Training Centre located in theMidlands province of Zimbabwe, to determine the effect of planting date and fertilizertypes in enhancing the productivity of spider plant, an indigenous leafy vegetable. Theexperimental design was a split- plot arranged in a randomized complete block design(RCBD) with three blocks. The planting date was the main plot with three levels(15/10/12, 30/01/13 and 15/02/13) and the fertilizer treatments as the subplots withseven levels including a control (no fertilizer applied), 20 t/ha cattle manure, 30 t/hacattle manure, 5 t/ha poultry manure, 10 t/ha poultry manure, 300 kg/ha Compound D +100 kg/ha ammonium nitrate and 300 kg/ha Compound D + 150 kg/ha ammoniumnitrate). Growth parameters, vitamin A and C, crude protein, iron content, fresh and dryyield were significantly (p<0.05) increased by use of organic and inorganic fertilizersacross all planting dates compared to the control where no fertilizers were added. TheOctober 2012 planting date, combined with high rates of organic and inorganicfertilizers had the best response with regards to the variables measured, including theduration of the harvest period which was nine weeks, compared to the January andFebruary planting dates where harvesting was for six weeks. The inorganic fertilizersprovided readily available nutrients for uptake by the plants while the long productionperiod for the October 2012 planting date enabled the organic manures (cattle andpoultry manure) adequate time to release the nutrients for uptake, compared to theJanuary 2013 and February 2013 planting dates. It can be concluded that there is meritin staggering the planting dates while using organic and inorganic fertilizers as thepractice results in an extended harvest period. High rates of both inorganic and organicfertilizers are recommended for the different planting dates as follows; 30 t/ha cattlemanure, 10 t/ha poultry manure, 300 kg/ha Compound D + 100 kg/ha ammoniumnitrate and 300 kg/ha Compound D + 150 kg/ha ammonium nitrate.Key words: Indigenous vegetable, spider plant, planting dates, fertilizers, nutrient